Skip to main content

Full text of "The planets"

See other formats


©^ap. ©tqnjrigijt Ifn. 

Shelf jJAL5/2_ 


" ^ .-..-'■-' ~-~ ■■ --'-'■■ 

mm mmmm. 

i — 

M Number 

Ifonu <&olh%z juries. 











The '-Home College Series '* will contain one hundred short papers on 
a wide range of subjects — biographical, historical, scientific, literary, domes- 
tic, political, and religious. Indeed, the religious tone will characterize all 
of them. They are written for every body — for all whose leisure is limited, 
but who desire to use the minutes for the enrichment of life. 

These papers contain seeds from the best gardens in all the world of 
human knowledge, and if dropped wisely into good soil, will bring forth 
harvests of beauty and value. 

They are for the young — especially for young people (and older people, 
too,) who are out of the schools, who are full of "business" and ;: fares," 
who are in danger of reading nothing,»or of reading a sensatioual literature 
that i3 worse than nothing. 

One of these papers a weekTead over and over, thought and talked about 
at "odd times," will give in one year a vast fund of information, an intel- 
lectual quickening, worth even more than the mere knowledge acquired, a 
taste for solid reading, many hours of simple and wholesome pleasure, and 
ability to talk intelligently and helpfully to one's friends. 

Pastors may organize "Home College" classes, or "Lyceum Reading 
Unions," or "Chautauqua Literary and Scientific Circles," and help the 
young people to read and think and talk and live to worthier purpose. 

A young man may have his own little "college," all by himself, read this 
series of tracts one after tire "Other, (there wifLSoon be one hundred of them 
ready,) examine himself on them by the " Thought-Outline to Help the Mem- 
ory," and thus gain knowledge, and, what is better, a love of knowledge. 

And what a 3'oung man may do in this respect, a yonng woman, and both 

old men and old women, may do. 

J. H. Vincent. 

New York, Jan., 1883. 


Copyright, 18S3, by Phillips & Hunt, New York. 

I^omc CoIItgi Skxm. |tumbcr Ctomto 

In an early age the planets were classed among the stars. 
But we have been taught to distinguish the one from the 
other by the use of the telescope. Stars do not appear en- 
larged in" telescopes of the highest power, only the more 
intensely brilliant ; while planets become greatly magnified, 
and many of their surface peculiarities visible. The reason 
is obvious. The stars are at an immense distance from the 
earth, but the planets are comparatively near neighbors to us, 
belonging, indeed, to the same family or solar system. Besides 
this difference in distance, we find all stars are suns, shining 
by their own light; whereas planets are worlds, such as our 
earth, and shine simply with the reflected light of the sun. 
These distinctions between stars and planets were, in. the 
main, unknown prior to the golden age of astronomy, which 
was inaugurated by the discovery of the telescope. A dif- 
ference, however, had been observed. Certain stars did not 
conform to the general order of grouping and motion, but 
seemed to move in an irregular and uncertain way from one 
constellation to another. These stars were a source of sin- 
gular conceits, as well as great perplexity, to early astrono- 
mers, who denominated them planets, or wanderers. 

Possibly the eccentric behavior of these " wandering stars " 
was the occasion for the rise of Astrology. The forecasting 
of events by the aspects, movements, etc., of the heavenly 
bodies is of remote antiquity. They were early supposed, 
as the representatives of fortune, to exercise a baneful, good, 
or mixed influence over individuals and nations. The seem- 
ingly arbitrary and irregular movements of the planets 
could not fail to excite interest, and, doubtless, secured for 
them the important place which they occupied, among the 


heavenly bodies, in this most elaborate and fanciful science 
of Astrology. While it is now generally conceded that the 
true theory of the movements of the solar system is of even 
more remote antiquity than astrological superstition, yet the 
details of this superstition are no more complex than the 
absurd theory proposed by Ptolemy of Alexandria, in the 
second century, to account for the strange movements of the 

I. The Solar System. 

Ptolemy's theory was in part anticipated, prior to his 
time, by many grave philosophers of heathen nations, who 
reasoned from the sun, moon, and stars rising in the east 
and setting in the west, that these revolved around the earth 
as the central world. They regarded the earth as flat, and 
at rest. They believed the idea of its moving through space 
to be contrary to the evidence of the human senses. The 
appearance of comets, meteors, and shooting stars served to 
strengthen this conviction. However, they realized great 
difficulty in attempting to reconcile certain astronomical 
phenomena with this theory. What supports and keeps the 
earth in its place ? was one of the perplexing questions, and 
the occasion of many absurd notions. By some nations it 
was asserted the earth rested upon the shoulders of a mighty 
bull ; among others, it was said to be supported by a great 
elephant ; while the common notion of the Hindus was that 
it rested upon the back of a tortoise, and that earthquakes 
are the result of his changing the foot on which he stands 
when weary. No attempt was made in these ridiculous and 
childish theories to explain what supported the animal on 
which the world rested. 

The illustrious Ptolemy, prosecuting his astronomical re- 
searches mainly for astrological purposes, maintained, in 
company with the heathen philosophers, that the earth was 
the center of the universe, and that all the heavenly bodies 


revolved about it in the course of twenty-four hours. He 
broke with traditionary superstitions, however, in affirming 
the rotundity of the earth and in approximation to the true 
idea, which finds expression in the Scripture language of 
Job — the oldest book in the world — " He stretcheth out the 
north over the empty place, and hangeth the earth upon 
nothing.' 1 He gave his strange mixture of truth and error 
a show of reason by affirming the heavens to be composed 
of a number of moving crystalline spheres, one above an- 
other, and in which were fixed the stars, sun, moon, and 
planets in the order of their nearness to the earth. Every 
heavenly body, he assumed, moves in an exact circle around 
a center, and this center in a circle around the earth. This 
latter circle he called a cycle, and the former an epicycle. 
To account for the difference of speed in planetary move- 
ments, he further assumed the eccentricity of these cycles. 
All this became the more complicated as the apparent mo- 
tion of the planets became the more accurately known. 
Aside from this complex absurdity, Ptolemy made many 
valuable and abiding contributions to astronomical science. 
Even this theory, so preposterously absurd, obtained as true 
science throughout the entire civilized world, until Nicholas 
Copernicus, in the fifteenth century, revived and demon- 
strated the truth of the Pythagorean theory, that the sun 
is the center of the system, and the earth, as one of the 
planets, moves around this center. Before the Ptolemaic 
era, Pythagoras taught this theory, which was rejected, be- 
cause unsupported by the requisite mathematical evidence, 
until the time of Copernicus. 

Somewhat after the revival of this Pythngorean theory, 
Kepler achieved immortality of fame by the discovery of 
the three great laws governing the motion of the planets, 
and the necessarily elliptical or oval-shaped orbits of the 
same. His theory did away with the complicated cycles and 
epicycles of Ptolemy; but required something additional to 


account for the perceptible though slight variations of these 
orbits from perfect ellipses. This needed addition was 
realized in Sir Isaac Newton's discovery of the law of grav- 
itation or attraction : " that law which, in its various modifi- 
cations, gives solidity alike to pebble and planet, and holds 
pebble and planet alike in place." 

" That very law which molds a tear, 

And bids it trickle from its source, 
That law preserves the earth a sphere, 

And guides the planets in their course." 

The Copernican theory, thus perfected, reveals the solar 
system, as connected by the mysterious force of gravita- 
tion, with the stars, but existing at the most remote dis- 
tance from them, and governed by its own physical laws. 
This theory, with an astonishing degree of accuracy, pre- 
dicts, for centuries to come, the courses of the planets and 
their satellites. It makes known the relative positions and 
importance of the different members of our world-family. 
The sun — with its dazzling brightness, welcome light, genial 
heat, evident influence upon animal and vegetable life ; 
greater mass of matter, 740 times larger than all the plan- 
ets combined; superior attractive power and repelling force; 
keeping the planets in their places — as the great controller, 
has the central and most prominent place in this theory, as 
he has by nature in the solar system. To obtain a clear idea 
of this system we would continue, as in natural order, with 
the sun ; but we have already considered that subject in a 
former article. Certain members of our world-family, such 
as comets and meteors, we reserve as of sufficient interest 
for a later article. 

The remaining members of our family circle are divided 
into two general classes : the planets, revolving around the 
gun; and the satellites, which, in their turn, revolve around 
while they accompany the planets in their journey about the 


solar orb. The planets, because of their very great differ- 
ence in size, are called major planets and minor planets. 
The latter are frequently denominated asteroids, signifying 
star-like worlds, or, more accurately still, planetoids, from 
their closer resemblance to planets. The major planets are 
divided by the asteroids into the natural and convenient 
classification of the inner group and the outer group. The 
inner group consists of those planets found between the aste- 
roids and the sun. They are as follows, with their mean 
distance in miles from, and in the order of their nearness to, 
the great central orb : Mercury, 35,800,000; Venus, 67,000,000; 
Earth, 92,000,000; Mars, 140,900,000. In the same order, 
those beyond the asteroids, or the outer group, are as fol- 
lows : Jupiter, 481,000,000 ; Saturn, 882,450,000 ; Uranus, 
1,774,000,000; Neptune, 2,780,000,000. 

II. Phenomena of the Planets, which, with various 


It is a natural supposition that there is much in our sister 
planets analogous to what we find over our own globe. But, 
as a matter of fact, we find greater diversity than similarity. 
With points of contrast marked and numerous, all have 
some features of resemblance. Yet even these are subject to 
various modifications, resulting in minor differences and 
suggesting strange and interesting possibilities. Hence, it 
is only with limitations that we can say the same period- 
ical changes are experienced, the same celestial phenomena 
are observed, on all the planets, as with us. They have 
alternation of day and night, of summer and winter. For 
them the sun has been set to rule the day, and moons and 
stars to rule the night. But we must remember that the 
time of revolution of a planet around the sun, whatever it 
be, is its year, and that of its revolution on its axis its day. 
We must bear in mind the inclination of a planet's axis to 


its orbit determines its seasons. Obviously, the differences 
in the planets of inclination of axis, orbital and axial revo- 
lutions and distance from the sun, carry with them corre- 
sponding differences in days and nights, years and seasons. 
We may get an idea of the relative positions and movements 
of the planets from the following explanation: 

The apparent path of the sun in the heavens is, in reality, 
the orbit or path of the earth, in its yearly revolution 
around the sun. This path is called the ecliptic, and its 
imaginary plane passes through the center of the zodiac, 
which is sixteen degrees in breadth. The zodiac comprises 
all the planetary paths ; it is the world-path of our system, 
and extends to eight degrees beyond each side of the plane 
of the ecliptic. In this world-path — never outside of it — all 
the planets move from east to west around the sun, except 
a few of the asteroids or minor planets. The difference be- 
tween a planet's orbit and the plane of the ecliptic is called 
its orbital inclination. The orbit, or path, of a planet is 
elliptical, and hence it is sometimes nearer and sometimes 
farther from the sun. This difference is called the orbital 
eccentricity of a planet. A consideration of these distinc- 
tions, in common with a comparison of the several mean 
distances of the planets from the sun, cannot but prove 
interesting. It approximates the truth to say, the distance 
of any planet from the one next to it, and nearer the sun, is 
but one half the distance to the next planet that is farther 
from the sun. Perhaps this was nothing more than a sin- 
gular coincidence, yet, even as such, it required a planet be- 
tween Mars and Jupiter, where no planet had been found. 
While searching for it the asteroids were discovered, one 
after the other, until 225 are now known, with the possibil- 
ity, as Leverrier affirms, of 150,000 in all. Among these are 
the only planets whose orbital inclination takes them out- 
side the zodiac. Hence their road- way or zone of space is 
much wider than that of the larger planets, their orbits 


slanting about in different directions in a very complicated 
fashion. " If a neat model were made of this zone, with a 
slender piece of wire to represent each orbit, it would be 
found impossible to lift up one wire without pulling up all 
the rest." The mean distance of the asteroids from the sun 
is 250,000,000 miles. Distance from the sun affects axial 
and orbital motion. The sun's attractive influence dimin- 
ishes as the square of the distance increases ; and we find 
diminution of orbital velocity corresponding to the sun's 
weakened force of attraction. The converse of this is also 
true : great centrifugal — center-fleeing — force is required to 
counterbalance great centripetal — center-seeking — power. 
Hence Mercury's orbital velocity must be over 168 miles a 
minute, or be drawn into the sun ; while Neptune, seventy- 
five times as far off, must move at the modified rate of 
twenty miles a minute to prevent it from flying beyond the 
sun's control Since Neptune is thirty times farther from 
the sun than we are, the luminary of day must appear there 
no larger than one of the planets does to us. If it has no 
other sources of heat and light than those which we have, 
what a cold, gloomy, cheerless world it must be ! — noonday 
no brighter than our twilight, and the mid-summer far colder 
than the coldest period of our icy north. On the other 
hand, the marked eccentricity and the nearness to the sun 
of Mercury's orbit gives that planet a view of the sun as 
nine times larger than it is to us, and from which it receives 
such intense light and heat that — if it ever had any — its 
oceans, lakes, and rivers must, long ago, have disappeared 
in vapor. If these planets have animal and vegetable life, 
in both instances they must exist under far different con- 
ditions from those which obtain on our globe. All the other 
planets lie between these two extremes of orbital velocity, 
light, heat, and cold, and perhaps bear less resemblance to 
them than they do in these and other particulars to our own 
planet. Nearly the same inclination of axis is observed in 


Earth, Mars, and Saturn; and, in consequence, these planets 
have very much the same changes of seasons, but differing 
in the period of time necessary to complete a season. The 
brilliant white spots at either pole of Mars, supposed by 
astronomers to be masses of snow, are observed to diminish 
at the approach of martial summer, and to increase at tlie 
approach of winter. These seasons cover a period of time 
but little greater than our own, while Saturn has seasons 
seven and a half years long ; a polar day of about fifteen 
years, and a polar night of about the same duration. We 
do not know the inclination of Neptune's axis ; but, if it is 
like our own, there are at its poles days equal to eighty-two 
and a half of our years, succeeded by nights of an equal 
length. An inhabitant there of the average age of man 
might never see daylight or never see the darkness of night. 
The axis of Uranus is nearly, if not quite, parallel to the 
plane of its orbit, and therefore its seasons are unknown. 
Perhaps, to the "[Iranians, the sun appears to wind around 
their globe in a spiral form. 

Jupiter's axis is perpendicular to the plane of its orbit, 
and, therefore, this planet has no varying seasons. In the 
same latitude, at the tropics, it is always summer ; at the 
poles, always winter ; and at the temperate zone, always 
spring. If the great inclination ascribed to the axis of Ve- 
nus is correct, this planet possesses the most remarkable 
seasons. For sixteen weeks it presents the south pole to the 
sun, and for the same period the north pole. And thus in 
thirty-two weeks its equator has two springs, two summers, 
two autumns, and two winters ; while, in the meantime, its 
poles have been alternately scorching or freezing. The time 
of a planet's axial rotation is its day. This time varies with 
different planets. The difference is so slight between the 
individual members of either group, that, it is sufficiently 
correct for our purpose to say, so far as known, they of the 
inner group rotate on their axes in about twenty-four hours, 


and they of the outer group in about ten hours. The effect 
of this high rate of motion, especially on the enormous 
bodies of the outer group, is a bulging at the equator, a loss 
of gravity from centrifugal force, and a shortening of the 
length of the day — Jupiter's day and night being reduced 
to five hours each. On the earth the motion at the equator 
is seventeen miles a minute, which gives it an equatorial 
diameter twenty-six miles greater than its polar diameter ; 
while Jupiter's equatorial motion is 467 miles a minute, and 
its polar diameter 5,000 less than its equatorial. Therefore, 
the oceans of Jupiter, through the simple agency of cen- 
trifugal force, are elevated above the common level of other 
zones — a mountain of water reaching the astonishing height 
of 2,500 miles. Before the equatorial velocity of Earth 
could approach anywhere near that of Jupiter, its oceans 
would leave the polar regions, rush to the equator, and bury 
the tallest mountains many fathoms deep, and from increas- 
ing velocity would spin off into space, leaving behind a 
waterless world ! Jupiter's superior volume — 1,300 times 
greater, though of less density, than our own planet — is, in 
a measure, counteracted by the effects of its greater speed 
of rotation. Yet the distinctions to which the differing sizes 
of the planets give rise are only slightly modified, not de- 
stroyed, by the differences in density of matter and in speed 
of rotation. 

Taking this into consideration, and the law of gravita- 
tion, that attraction is proportional to the quantity of 
matter, and varies inversely as the square of the distance 
from the center of the attracting body, it will be readily 
seen : the larger the world, the smaller must be its inhabit- 
ants, if constituted as they are on our own planet. Hence 
the inhabitants of Jupiter must be dwarfs, of the Earth mm, 
and of the asteroids giants / while their achievements are in 
proportion to their size, and inversely to the dimensions of 
the planet on which they live. 


III. Phenomena of the Planets peculiar to each, and 


Mercury, in a good telescope, as also Yenus, exhibits all 
the phases of the moon. Though nearly as bright as the 
star Sirius, it is difficult to see, because of its nearness to the 
sun and the horizon. For this same reason it is not certainly 
known if there be, though some astronomers affirm the exist- 
ence of, a planet between Mercury and the sun which they 
have named Vulcan. Traces of the most tremendous vol- 
canic action have been discovered on Mercury. Enormous 
mountains have been observed, one at least ten miles in 
height, twice that of any known elevation on our globe. 

Mercury, and also Venus, at certain stated periods, pass 
directly between the earth and the sun, and have the ap- 
pearance of crossing the sun's disk. This is called a transit. 
One of Venus occurred last year, (1882,) but will not occur 
again for 122 years. Being used as a means of ascertaining 
the sun's distance from the earth, the event created, as it 
always does, a great stir in astronomical circles. The astron- 
omer of to-day, gazing upon this transit of Venus, can say 
with the young English curate, Jeremiah Horrox, when he 
witnessed the one of December 4, 1639 : 

""We with anxious mind follow thy footsteps here, and far 

As the sight can carry us ; ray labors now 

Bedeck the monument for future times, 

"Which thou at parting left us. Thy return 

Posterity shall witness ; years must roll 

Away, but then at length the splendid sight 

Again shall greet our distant children's eyes ! " 

Venus, the most brilliant of all the planetary orbs, like 
Mercury, and for the same reason, is seen about sunrise and 
sunset. At rare intervals she may be seen, with singular 
and striking beauty, softly shining, while the sun is yet high 
in the heavens. This fail* orb thus appeared when the first 


Napoleon was making one of his triumphant entries into 
Paris, and was hailed by both multitude and conqueror as a 
significant and pleasing omen. It is possible we never see 
more than the illuminated atmosphere of Venus ; while on 
Mars, the nearest planet outside the earth's orbit, we can 
trace with perfect distinctness the outlines of continents and 
seas. Mars is the reddest star in the heavens. This may be 
due to its atmosphere, the color of its soil, or the predomi- 
nant color of its vegetation. Altogether it is, so far as we 
know, more like our globe than any of the other planets. It 
may have sunset and sunrise effects as we have them here : 
fields wrapped in twilight darkness, soft purple shadows 
creeping up or down the hills, crags and peaks tapestried 
with light, and mountain-tops gleaming in silver and gold. 
It may have the still more glorious northern lights, with its 
infinite variety of form, reaching far above its clouds, and 
even hundreds of miles beyond its atmosphere. Its atmo- 
sphere may serve, as with us, to give additional loveliness to 
the beautiful in the landscape, the tints of flowers, and the 
bright plumage of birds. Jupiter is the king planet, be- 
cause the largest in size. This planet is characterized by 
the changeful stripes or belts across his disk and the attend- 
ance of four satellites, which revolve around it as the moon 
does around us. 

Galileo discovered these moons, but had difficulty in con- 
vincing others of their existence, because they persistently 
refused the use of the telescope. Libri, of Pisi, died still 
skeptical ; and Galileo, in a letter to a friend, expressed the 
charitable hope that Libri went to heaven by way of the 
planet Jupiter, and was now convinced of the existence of 
its satellites. These moons are often seen with a good two- 
inch telescope. Lunar eclipses are quite frequent, and have 
furnished the means for discovering the velocity of light. 
Occasionally several occur at the same time, and present 
glories of the sky outrivaling our own. 


The largest planet except Jupiter, and the most iconder- 
ful, is Saturn. It is attended by eight satellites, and under 
the telescope presents the most extraordinary appearance. 
Around this planet are seen three, and by some five, luminous, 
concentric, whirling rings, one of which shines with even 
greater splendor than the planet itself. These rings are 
very broad and thin, with the inner edge always turned to- 
ward the planet's equator, and occasionally the outer edge 
turned directly toward the earth, in which case they disap- 
pear even though our sight be aided by a powerful telescope. 
Galileo was so amazed at this that he asked, " Is the legend 
of mythology no longer a fable, and has Saturn really de- 
voured his children?" In attempting to ascertain the nature 
and origin of these rings, Maupertus suggested the quaint 
theory that " they might be the mangled remains of an un- 
fortunate comet which had incautiously come too near Sat- 
urn, and got his tail wound round the planet and twisted 
off." The nature and origin of these rings has long puzzled 
mathematicians and astronomers without very satisfactory 
results. In beholding thunderous Niagara or towering Alps 
we experience less of awe and solemnity than we do when, 
with powerful telescope, we see this strange mechanism of 
planet, whirling rings and revolving satellites dashing through 
space at 21,000 miles an hour. 

Next in order of distance from the sun is Uranus, for 
some time supposed to be the outermost planet of our sys- 
tem. It was discovered by Sir William Herschel, whose 
name it sometimes bears. It has four moons which, contrary 
to all precedent, move in a retrograde direction, revolving 
nearly over its .poles. The orbit of this planet presented 
irregularities which for years were unaccountable to astron- 
omers. Bouvard suggested an unknown outside planet. 
Herschel used the following significant language of a planet 
beyond Uranus : " We see it as Columbus saw America 
from the shores of Spain. Its movements have been felt 


trembling along the far-reaching line of our analysis with 
a certainty not much inferior to ocular demonstration." 

Adams, of England, and Leverrier, of France, assumed the 
task of accounting for its perturbations. Each one, by the 
most extraordinary mental achievements known to the sci- 
entific world, succeeded in ascertaining the mass, orbit, and 
actual position of Neptune before mortal eye ever con- 
sciously gazed upon it. This planet was discovered first at 
Berlin, and then at Cambridge, England, by looking at the 
place indicated by these men. 

How impressively grand and beautiful is the solar system 
as it appears in a general view ! We see its 253 members, 
all whirling on their axes as they go bowling along their 
great highway of the skies in perfect harmony and order, 
and never encroaching the one on the other's domain. We 
see all these bodies with their intricate movements accom- 
panying the sun in its mighty sweep of 18,000,000 years for 
a single journey around a far distant and, as yet, scarcely 
known center. We are overwhelmed by the amazing spec- 
tacle ; we are awed into silence before a power which no 
less displays the might of God in swinging the planets than 
in the activities of living worlds, or the palpitating, strug- 
gling, thundering forces on the worlds in process of forma- 
tion ! Yet, in this view, we see only an infinitesimal part 
of God's revelation of his omnipotence and wisdom. Shall 
we seek a broader range of vision ? Before us lies the uni- 
verse of stars — a universe comprehending such distances and 
displaying such wisdom and energy as to far surpass human 
conception or description. Of this universe we hope to see 
and say more in a future paper, and seek now only a brief 
glimpse as we pass from the present subject. 

Neptune has been styled " the last sentinel upon the out- 
posts" of the king of day, who sends his comets as scouts 
„into space far beyond. Upon the wings of thought we travel, 
with the " king's scouts," until they, too, reach their utter- 


most distance from the sun, and, feeling the check of his 
power, curve backward in their course. We borrow the 
speed of light and continue our journey. From the confines 
of the solar system we range the unfathomable depths above, 
beneath, around, and every-where find new worlds. We pass 
mighty constellations, sweep by huge suns with their planet- 
ary worlds, leave millions of stars and hundreds of millions 
of moons and planets behind, that, traveling at the rate of 
185,000 miles per second, it has taken us hundreds of years 
to reach, and still find ourselves but penetrating the outskirts 
of God's universe. 

" Lo, these are parts of his ways ; but how little a portion 
is heard of him ? but the thunder of his power who can un- 
derstand?" (Job.) We will not presume to say, with Kep- 
ler, " O God, I think thy thoughts after thee ; " but, more 
modestly, with David, " O Lord, how great are thy works ! 
and thy thoughts are very deep : " " who hast set thy glory 
above the heavens." 

" Enrich me with the knowledge of thy works ! 
Snatch me to heaven ; thy rolling wonders there, 
"World beyond world in infinite extent, 
Profusely scattered o'er the blue immense, 
Show me. Their motions, periods, and their laws, 
Give me to scan. Through the disclosing deep 
Light my blind way." 

The Solar System. 

"The sun revolving on his axis turns, 
And with created fire intensely burns ; 
Impell'd the forcive air, our earth supreme 
Rolls with the planets round the solar gleam. 
First Mercury completes his transient year, 
Glowing refulgent with reflected glare ; 
Bright Venus occupies a wider way, 
The early harbinger of night and day. 
More distant still our globe terraqueous turns, 
Nor chills intense, nor fiercely heated burns : 


Around her rolls the lunar orb of light, 

Trailing her silver glories through the night. 

Beyond our globe the sanguine Mars displays 

A strong reflection of primeval rays : 

The group of asteroids in order move 

Between the planets Mars and mighty Jove. 

Next belted Jupiter far distant gleams, 

Scarcely enlightened with the solar beams. 

With four unfixed receptacles of light 

He towers majestic through the spacious height ; 

But farther yet the tardy Saturn lags, 

And eight attendant luminaries drags ; 

Investing with a double ring his pace, 

He travels through immensity of space. 

Next, see Uranus wheeling wide his round 

Of fourscore years ; not unassisted found 

By human eye; the telescope displays 

Him, with six moons, to philosophic gaze. 

Still more remote, pale Neptune wends his way; 

Leverrier's skill divined his distant ray. 

His lengthened year, by his slow moving pace, 

A hundred sixty -four of ours may trace." 

" It is to astronomy we are indebted for our only accurate 
measures of time. The first period noted by man was, no 
doubt, counted by days, or suns, then by months, or moons ; 
after which the apparent annual revolution of the sun gave 
the idea of a year." — Hannah M. Bouvier. 

" Blest power of sunshine, genial day ! 

What balm, what light, is in thy ray! " — Lalla Roqkh. 

11 Day takes his daily turn, 

Rising between the gulfy dells of night, 

Like whitened billows on a gloomy sea." — Joanna Baillie. 

" These as they change, Almighty Father 1 these 
Are but the varied G-od. The rolling year 
Is full of thee." — Thomson's " Seasons." 


" Go ! all the sightless realms of space survey ; 

Returning, trace the planetary way; 

The sun that in his central glory shines, 

While every planet round his orb inclines; 

Then at our intermediate globe repose, 

And view yon stellar satellite that glows. 

Or cast along the azure vault thine eye, 

When golden day enlightens all the sky; 

Around, behold earth's variegated scene, 

The mingling prospects and the flowery green; 

The mountain's brow ; the long-extended wood, 

Or the rude rock that threatens o'er the flood ; 

And say, are these the wild effects of chance ? 

0, strange effect of reasoning ignorance ! " — Boyse. 

" The flower that opened its frail beauty within reach of 
the observer's hand, the wild bird that lifted up its morning 
song in welcome of the returning light, the evening cloud 
that curtained the couch of the setting sun with its crimson 
glory, the rainbow that spanned the pathway of the retiring 
storm with its sevenfold arch, might indeed for a few mo- 
ments arrest a more vivid and delighted attention ; but 
when they had finished their brief course and had sunk into 
silence and darkness, the lifted eye could see the same stars 
blooming like fire-tinted blossoms on the plains of heaven, 
undimmed by the darkness of a thousand storms, unchanged 
by the lapse of a thousand years." — Daniel March. 

[thought-outline to help the memory.] 

1. Planets and Stars— Differences ? Origin of Astrology ? 

2. Old theories of Solar System by heathen philosophers? Ptolemy's theory? 

Copernicus' theory? The "great controller?" Planets? Satellites? 
Asteroids ? Planetoids? Distances from the sun ? 

3. Phenomena of planets — in common? Some features of resemblance ? Cause 

of day and night ? Of seasons ? * ' World-path ? " " Orbital inclination ? " 
" Orbital eccentricity? "